[PATCH V4 3/4] ARM: add basic support for the Broadcom BCM2835 SoC
Stephen Warren
swarren at wwwdotorg.org
Sun Aug 5 22:07:21 EDT 2012
This SoC is used in the Raspberry Pi, for example.
For more details, see:
http://www.broadcom.com/products/BCM2835
http://www.raspberrypi.org/wp-content/uploads/2012/02/BCM2835-ARM-Peripherals.pdf.
Initial support is enough to boot to a serial console, execute a minimal
set of U-Boot commands, download data over a serial port, and boot a
Linux kernel. No storage or network drivers are implemented.
GPIO driver originally by Vikram Narayanan <vikram186 at gmail.com>
with many fixes from myself.
Signed-off-by: Stephen Warren <swarren at wwwdotorg.org>
---
v4: No change
v3: Squash base SoC, watchdog, and GPIO driver patches into one.
---
arch/arm/cpu/arm1176/bcm2835/Makefile | 37 +++++++++++
arch/arm/cpu/arm1176/bcm2835/config.mk | 19 ++++++
arch/arm/cpu/arm1176/bcm2835/lowlevel_init.S | 19 ++++++
arch/arm/cpu/arm1176/bcm2835/reset.c | 35 ++++++++++
arch/arm/cpu/arm1176/bcm2835/timer.c | 55 ++++++++++++++++
arch/arm/include/asm/arch-bcm2835/gpio.h | 66 +++++++++++++++++++
arch/arm/include/asm/arch-bcm2835/timer.h | 37 +++++++++++
arch/arm/include/asm/arch-bcm2835/wdog.h | 37 +++++++++++
drivers/gpio/Makefile | 1 +
drivers/gpio/bcm2835_gpio.c | 90 ++++++++++++++++++++++++++
10 files changed, 396 insertions(+)
create mode 100644 arch/arm/cpu/arm1176/bcm2835/Makefile
create mode 100644 arch/arm/cpu/arm1176/bcm2835/config.mk
create mode 100644 arch/arm/cpu/arm1176/bcm2835/lowlevel_init.S
create mode 100644 arch/arm/cpu/arm1176/bcm2835/reset.c
create mode 100644 arch/arm/cpu/arm1176/bcm2835/timer.c
create mode 100644 arch/arm/include/asm/arch-bcm2835/gpio.h
create mode 100644 arch/arm/include/asm/arch-bcm2835/timer.h
create mode 100644 arch/arm/include/asm/arch-bcm2835/wdog.h
create mode 100644 drivers/gpio/bcm2835_gpio.c
diff --git a/arch/arm/cpu/arm1176/bcm2835/Makefile b/arch/arm/cpu/arm1176/bcm2835/Makefile
new file mode 100644
index 0000000..4ea6d6b
--- /dev/null
+++ b/arch/arm/cpu/arm1176/bcm2835/Makefile
@@ -0,0 +1,37 @@
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# version 2 as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+
+include $(TOPDIR)/config.mk
+
+LIB = $(obj)lib$(SOC).o
+
+SOBJS := lowlevel_init.o
+COBJS := reset.o timer.o
+
+SRCS := $(SOBJS:.o=.c) $(COBJS:.o=.c)
+OBJS := $(addprefix $(obj),$(SOBJS) $(COBJS))
+
+all: $(obj).depend $(LIB)
+
+$(LIB): $(OBJS)
+ $(call cmd_link_o_target, $(OBJS))
+
+#########################################################################
+
+# defines $(obj).depend target
+include $(SRCTREE)/rules.mk
+
+sinclude $(obj).depend
+
+#########################################################################
diff --git a/arch/arm/cpu/arm1176/bcm2835/config.mk b/arch/arm/cpu/arm1176/bcm2835/config.mk
new file mode 100644
index 0000000..b87ce24
--- /dev/null
+++ b/arch/arm/cpu/arm1176/bcm2835/config.mk
@@ -0,0 +1,19 @@
+#
+# (C) Copyright 2012 Stephen Warren
+#
+# See file CREDITS for list of people who contributed to this
+# project.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# version 2 as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+
+# Don't attempt to override the target CPU/ABI options;
+# the Raspberry Pi toolchain does the right thing by default.
+PLATFORM_RELFLAGS := $(filter-out -msoft-float,$(PLATFORM_RELFLAGS))
+PLATFORM_CPPFLAGS := $(filter-out -march=armv5t,$(PLATFORM_CPPFLAGS))
diff --git a/arch/arm/cpu/arm1176/bcm2835/lowlevel_init.S b/arch/arm/cpu/arm1176/bcm2835/lowlevel_init.S
new file mode 100644
index 0000000..c7b0843
--- /dev/null
+++ b/arch/arm/cpu/arm1176/bcm2835/lowlevel_init.S
@@ -0,0 +1,19 @@
+/*
+ * (C) Copyright 2012 Stephen Warren
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+.globl lowlevel_init
+lowlevel_init:
+ mov pc, lr
diff --git a/arch/arm/cpu/arm1176/bcm2835/reset.c b/arch/arm/cpu/arm1176/bcm2835/reset.c
new file mode 100644
index 0000000..8c37ad9
--- /dev/null
+++ b/arch/arm/cpu/arm1176/bcm2835/reset.c
@@ -0,0 +1,35 @@
+/*
+ * (C) Copyright 2012 Stephen Warren
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/wdog.h>
+
+#define RESET_TIMEOUT 10
+
+void reset_cpu(ulong addr)
+{
+ struct bcm2835_wdog_regs *regs =
+ (struct bcm2835_wdog_regs *)BCM2835_WDOG_PHYSADDR;
+ uint32_t rstc;
+
+ rstc = readl(®s->rstc);
+ rstc &= ~BCM2835_WDOG_RSTC_WRCFG_MASK;
+ rstc |= BCM2835_WDOG_RSTC_WRCFG_FULL_RESET;
+
+ writel(BCM2835_WDOG_PASSWORD | RESET_TIMEOUT, ®s->wdog);
+ writel(BCM2835_WDOG_PASSWORD | rstc, ®s->rstc);
+}
diff --git a/arch/arm/cpu/arm1176/bcm2835/timer.c b/arch/arm/cpu/arm1176/bcm2835/timer.c
new file mode 100644
index 0000000..d232d7e
--- /dev/null
+++ b/arch/arm/cpu/arm1176/bcm2835/timer.c
@@ -0,0 +1,55 @@
+/*
+ * (C) Copyright 2012 Stephen Warren
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <asm/arch/timer.h>
+
+int timer_init(void)
+{
+ return 0;
+}
+
+ulong get_timer(ulong base)
+{
+ struct bcm2835_timer_regs *regs =
+ (struct bcm2835_timer_regs *)BCM2835_TIMER_PHYSADDR;
+
+ return readl(®s->clo) - base;
+}
+
+unsigned long long get_ticks(void)
+{
+ return get_timer(0);
+}
+
+ulong get_tbclk(void)
+{
+ return CONFIG_SYS_HZ;
+}
+
+void __udelay(unsigned long usec)
+{
+ ulong endtime;
+ signed long diff;
+
+ endtime = get_timer(0) + usec;
+
+ do {
+ ulong now = get_timer(0);
+ diff = endtime - now;
+ } while (diff >= 0);
+}
diff --git a/arch/arm/include/asm/arch-bcm2835/gpio.h b/arch/arm/include/asm/arch-bcm2835/gpio.h
new file mode 100644
index 0000000..0e70856
--- /dev/null
+++ b/arch/arm/include/asm/arch-bcm2835/gpio.h
@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2012 Vikram Narayananan
+ * <vikram186 at gmail.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _BCM2835_GPIO_H_
+#define _BCM2835_GPIO_H_
+
+#define BCM2835_GPIO_BASE 0x20200000
+#define BCM2835_GPIO_COUNT 54
+
+#define BCM2835_GPIO_FSEL_MASK 0x7
+#define BCM2835_GPIO_INPUT 0x0
+#define BCM2835_GPIO_OUTPUT 0x1
+#define BCM2835_GPIO_ALT0 0x4
+#define BCM2835_GPIO_ALT1 0x5
+#define BCM2835_GPIO_ALT2 0x6
+#define BCM2835_GPIO_ALT3 0x7
+#define BCM2835_GPIO_ALT4 0x3
+#define BCM2835_GPIO_ALT5 0x2
+
+#define BCM2835_GPIO_COMMON_BANK(gpio) ((gpio < 32) ? 0 : 1)
+#define BCM2835_GPIO_COMMON_SHIFT(gpio) (gpio & 0x1f)
+
+#define BCM2835_GPIO_FSEL_BANK(gpio) (gpio / 10)
+#define BCM2835_GPIO_FSEL_SHIFT(gpio) ((gpio % 10) * 3)
+
+struct bcm2835_gpio_regs {
+ u32 gpfsel[6];
+ u32 reserved1;
+ u32 gpset[2];
+ u32 reserved2;
+ u32 gpclr[2];
+ u32 reserved3;
+ u32 gplev[2];
+ u32 reserved4;
+ u32 gpeds[2];
+ u32 reserved5;
+ u32 gpren[2];
+ u32 reserved6;
+ u32 gpfen[2];
+ u32 reserved7;
+ u32 gphen[2];
+ u32 reserved8;
+ u32 gplen[2];
+ u32 reserved9;
+ u32 gparen[2];
+ u32 reserved10;
+ u32 gppud;
+ u32 gppudclk[2];
+};
+
+#endif /* _BCM2835_GPIO_H_ */
diff --git a/arch/arm/include/asm/arch-bcm2835/timer.h b/arch/arm/include/asm/arch-bcm2835/timer.h
new file mode 100644
index 0000000..30c70e0
--- /dev/null
+++ b/arch/arm/include/asm/arch-bcm2835/timer.h
@@ -0,0 +1,37 @@
+/*
+ * (C) Copyright 2012 Stephen Warren
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _BCM2835_TIMER_H
+#define _BCM2835_TIMER_H
+
+#define BCM2835_TIMER_PHYSADDR 0x20003000
+
+struct bcm2835_timer_regs {
+ u32 cs;
+ u32 clo;
+ u32 chi;
+ u32 c0;
+ u32 c1;
+ u32 c2;
+ u32 c3;
+};
+
+#define BCM2835_TIMER_CS_M3 (1 << 3)
+#define BCM2835_TIMER_CS_M2 (1 << 2)
+#define BCM2835_TIMER_CS_M1 (1 << 1)
+#define BCM2835_TIMER_CS_M0 (1 << 0)
+
+#endif
diff --git a/arch/arm/include/asm/arch-bcm2835/wdog.h b/arch/arm/include/asm/arch-bcm2835/wdog.h
new file mode 100644
index 0000000..d750a62
--- /dev/null
+++ b/arch/arm/include/asm/arch-bcm2835/wdog.h
@@ -0,0 +1,37 @@
+/*
+ * (C) Copyright 2012 Stephen Warren
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef _BCM2835_TIMER_H
+#define _BCM2835_TIMER_H
+
+#define BCM2835_WDOG_PHYSADDR 0x20100000
+
+struct bcm2835_wdog_regs {
+ u32 unknown0[7];
+ u32 rstc;
+ u32 unknown1;
+ u32 wdog;
+};
+
+#define BCM2835_WDOG_PASSWORD 0x5a000000
+
+#define BCM2835_WDOG_RSTC_WRCFG_MASK 0x00000030
+#define BCM2835_WDOG_RSTC_WRCFG_FULL_RESET 0x00000020
+
+#define BCM2835_WDOG_WDOG_TIMEOUT_MASK 0x0000ffff
+
+#endif
+
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index 32a2474..8d2f2b2 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -40,6 +40,7 @@ COBJS-$(CONFIG_TEGRA_GPIO) += tegra_gpio.o
COBJS-$(CONFIG_DA8XX_GPIO) += da8xx_gpio.o
COBJS-$(CONFIG_ALTERA_PIO) += altera_pio.o
COBJS-$(CONFIG_MPC83XX_GPIO) += mpc83xx_gpio.o
+COBJS-$(CONFIG_BCM2835_GPIO) += bcm2835_gpio.o
COBJS := $(COBJS-y)
SRCS := $(COBJS:.o=.c)
diff --git a/drivers/gpio/bcm2835_gpio.c b/drivers/gpio/bcm2835_gpio.c
new file mode 100644
index 0000000..6ab2df3
--- /dev/null
+++ b/drivers/gpio/bcm2835_gpio.c
@@ -0,0 +1,90 @@
+/*
+ * Copyright (C) 2012 Vikram Narayananan
+ * <vikram186 at gmail.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <common.h>
+#include <asm/gpio.h>
+#include <asm/io.h>
+
+inline int gpio_is_valid(unsigned gpio)
+{
+ return (gpio < BCM2835_GPIO_COUNT);
+}
+
+int gpio_request(unsigned gpio, const char *label)
+{
+ return !gpio_is_valid(gpio);
+}
+
+int gpio_free(unsigned gpio)
+{
+ return 0;
+}
+
+int gpio_direction_input(unsigned gpio)
+{
+ struct bcm2835_gpio_regs *reg =
+ (struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE;
+ unsigned val;
+
+ val = readl(®->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+ val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio));
+ val |= (BCM2835_GPIO_INPUT << BCM2835_GPIO_FSEL_SHIFT(gpio));
+ writel(val, ®->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+
+ return 0;
+}
+
+int gpio_direction_output(unsigned gpio, int value)
+{
+ struct bcm2835_gpio_regs *reg =
+ (struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE;
+ unsigned val;
+
+ gpio_set_value(gpio, value);
+
+ val = readl(®->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+ val &= ~(BCM2835_GPIO_FSEL_MASK << BCM2835_GPIO_FSEL_SHIFT(gpio));
+ val |= (BCM2835_GPIO_OUTPUT << BCM2835_GPIO_FSEL_SHIFT(gpio));
+ writel(val, ®->gpfsel[BCM2835_GPIO_FSEL_BANK(gpio)]);
+
+ return 0;
+}
+
+int gpio_get_value(unsigned gpio)
+{
+ struct bcm2835_gpio_regs *reg =
+ (struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE;
+ unsigned val;
+
+ val = readl(®->gplev[BCM2835_GPIO_COMMON_BANK(gpio)]);
+
+ return (val >> BCM2835_GPIO_COMMON_SHIFT(gpio)) & 0x1;
+}
+
+int gpio_set_value(unsigned gpio, int value)
+{
+ struct bcm2835_gpio_regs *reg =
+ (struct bcm2835_gpio_regs *)BCM2835_GPIO_BASE;
+ u32 *output_reg = value ? reg->gpset : reg->gpclr;
+
+ writel(1 << BCM2835_GPIO_COMMON_SHIFT(gpio),
+ &output_reg[BCM2835_GPIO_COMMON_BANK(gpio)]);
+
+ return 0;
+}
+
--
1.7.9.5
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